The present invention relates to integrated voltage multipliers, i.e. the multipliers are constructed on the basis of multilayer technology.
Multistage voltage multipliers, like that shown diagrammatically in FIG. 1, comprise a cascade connection of capacitors and diodes and hitherto they have been constructed in various ways, as a function of the choice of components made.
These components are formed on the one hand by elementary capacitors generally ceramic dielectric capacitors in the form of a monolithic or multilayer disk or have a dielectric film and diodes. These components are arranged in series in the manner shown in FIG. 1, which represents a voltage multiplier known under the name Greinacher circuit. The capacitors used can also be obtained by the metallization of each of the faces of an e.g. ceramic or epoxy insulating plate, so that a series of capacitors is obtained, having similar characteristics with regards to the voltage and supply frequency on the one hand and the voltage and the output power on the other.
Thus, according to the prior art, in the construction of a voltage multiplier, active and passive components are used, which are assembled in accordance with the multiplier circuit diagram, followed by potting. The multiplier is in the form of a block in which various materials are adjacent to one another.
This leads to the disadvantages resulting from the different behaviour of these materials with respect to the climatic conditions. Thus, the glass of the diodes, the copper and lead-tin of the connections and welds, the ceramic or film of the capacitors and the protective resin react very differently to the climatic conditions and aging which, under the influence of the different thermal stresses, lead to changes in the characteristics and a deterioration of the performance levels. Account must also be taken of the very high voltage which, within the block, may cause leakage paths creating short-circuits of multiplier components.
In addition to the aforementioned disadvantages reference must also be made to the overall dimensions and volume occupied by the block forming the multiplier, so that at present the latter has a relatively large size which is not very compatible with what is required for certain applications, such as e.g. the scanning of the radar display, mainly in the case of the embarked version. It is by no means easy to reduce the volume of the presently known voltage multipliers because it would be necessary to take action with respect to the volume of each component, whose sum value, plus the spaces necessary for insulating each of them, gives the total volume of the multiplier unit.